    The following meanings for the abbreviations used in this specification apply:    3GPP 3rd generation partnership project    ETSI European Telecommunications Standards Institute    GW Gateway    I-CSCF Interrogating call server control function    ID Identity, Identifier    IMS IP multimedia subsystem    I/O Input/output    IP Internet protocol    ISG Industry specification group    LTE Long term evolution    MME Mobile management entity    NFVO Network functions virtualization orchestrator    O&M Operation & Maintenance    OS Operating system    PCRF Policy and charging rules function    P-CSCF Proxy call server control function    PE Physical environment    P-GW Packet data network gateway    PM Physical machine    S-CSCF Serving call server control function    SGSN Serving general packet radio service support node    S-GW Serving gateway    UE User equipment    VM Virtual machine    VNF Virtualized network function
Embodiments of the present invention relate to management for network entity selection. In particular, 3GPP mobile network contains a number of network entities that are selected from a number of similar entities by other kinds of entities that need to establish communication with the first kind of entities to enable user sessions. In many cases at least one of the selection criteria is network topology. The addresses or identities of the candidate entities are typically configured in the entity that shall select one entity from the candidate entities.
An example is MME which is selected by a radio network entity, e.g. eNodeB. Further packet core network examples of entities selected by another entity are S-GW and SGSN. (Refer to 3GPP TS 23.401 V12.2.0 (2013-09)/subclause 4.3.8). FIG. 3 reproduces FIG. 4.2.1-1 of 3GPP TS 23.401 V12.2.0 (2013-09) and shows a non-roaming architecture for 3GPP accesses. Examples of 3GPP network entities selected in such a way in IMS environment are P-CSCF which is selected by P-GW based on preconfigured P-CSCF addresses (refer to 3GPP TS 29.061 V12.3.0 (2013-09)/subclause 13a.2.1), S-CSCF which is selected by I-CSCF (refer to 3GPP TS 23.228 V12.2.0 (2013-09)/subclause 5.1.2.1). Further examples of entities selected from amongst a number of similar entities are PCRF and I-CSCF.
ETSI ISG NFV is studying network function virtualization concerning mobile network environment. In this environment the virtualized network entities are managed by the network function virtualization orchestrator (NFVO). The NFVO dynamically and automatically distributes and maintains virtualized network functions in the infrastructure, i.e. sets up virtual machines (VMs) to run on given physical machines (PMs) and sets up virtual network functions/entities to run on the VMs, defines and allocates and scales resources to the virtual entities and machines. The NVFO may also have an interface to legacy O&M functions to utilize existing O&M functionalities.
Concerning some network entities in 3GPP environment, a given/certain entity amongst a number of similar entities is selected by another entity for a user/UE, when the UE attaches the network or sets up a session (like e.g. an IMS session). Examples of such selectable entities are MME, S-GW, SGSN, PCRF, P-CSCF.
This kind of selection of network entities is to be supported also in virtualized environments.